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staging: iio: ad5933: Protect DIRECT mode using claim/release helpers 

This device operates in DIRECT_MODE and BUFFER_HARDWARE mode.
Replace usages of iio_dev->mlock with iio_device_{claim|release}_direct_mode()
helper functions to guarantee DIRECT mode and consequently protect
BUFFER mode too.

Add and use a device private lock to protect against conflicting access of the
state data.
This helps with IIO subsystem redefining iio_dev->mlock to be used by
the IIO core only for protecting device operating mode changes.
ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.

Protect changing of attributes inside ad5933_store(). Attributes
can no longer be changed while in buffered mode.

Remove lock from ad5933_work() because buffer mode should be enabled
when we reach this, and claiming DIRECT mode in all the other places
should protect it.

Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Narcisa Ana Maria Vasile 2017-04-09 13:40:07 +03:00 committed by Jonathan Cameron
parent a9e9c7153e
commit 984fb24430
1 changed files with 28 additions and 22 deletions
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50
drivers/staging/iio/impedance-analyzer/ad5933.c
View File

@ -98,6 +98,7 @@ struct ad5933_state {
struct i2c_client *client;
struct regulator *reg;
struct delayed_work work;
struct mutex lock; /* Protect sensor state */
unsigned long mclk_hz;
unsigned char ctrl_hb;
unsigned char ctrl_lb;
@ -306,9 +307,11 @@ static ssize_t ad5933_show_frequency(struct device *dev,
u8 d8[4];
} dat;
mutex_lock(&indio_dev->mlock);
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ret = ad5933_i2c_read(st->client, this_attr->address, 3, &dat.d8[1]);
mutex_unlock(&indio_dev->mlock);
iio_device_release_direct_mode(indio_dev);
if (ret < 0)
return ret;
@ -338,9 +341,11 @@ static ssize_t ad5933_store_frequency(struct device *dev,
if (val > AD5933_MAX_OUTPUT_FREQ_Hz)
return -EINVAL;
mutex_lock(&indio_dev->mlock);
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ret = ad5933_set_freq(st, this_attr->address, val);
mutex_unlock(&indio_dev->mlock);
iio_device_release_direct_mode(indio_dev);
return ret ? ret : len;
}
@ -364,7 +369,7 @@ static ssize_t ad5933_show(struct device *dev,
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
int ret = 0, len = 0;
mutex_lock(&indio_dev->mlock);
mutex_lock(&st->lock);
switch ((u32)this_attr->address) {
case AD5933_OUT_RANGE:
len = sprintf(buf, "%u\n",
@ -393,7 +398,7 @@ static ssize_t ad5933_show(struct device *dev,
ret = -EINVAL;
}
mutex_unlock(&indio_dev->mlock);
mutex_unlock(&st->lock);
return ret ? ret : len;
}
@ -415,7 +420,10 @@ static ssize_t ad5933_store(struct device *dev,
return ret;
}
mutex_lock(&indio_dev->mlock);
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&st->lock);
switch ((u32)this_attr->address) {
case AD5933_OUT_RANGE:
ret = -EINVAL;
@ -465,7 +473,8 @@ static ssize_t ad5933_store(struct device *dev,
ret = -EINVAL;
}
mutex_unlock(&indio_dev->mlock);
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return ret ? ret : len;
}
@ -532,11 +541,9 @@ static int ad5933_read_raw(struct iio_dev *indio_dev,
switch (m) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
if (iio_buffer_enabled(indio_dev)) {
ret = -EBUSY;
goto out;
}
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ret = ad5933_cmd(st, AD5933_CTRL_MEASURE_TEMP);
if (ret < 0)
goto out;
@ -549,7 +556,7 @@ static int ad5933_read_raw(struct iio_dev *indio_dev,
2, (u8 *)&dat);
if (ret < 0)
goto out;
mutex_unlock(&indio_dev->mlock);
iio_device_release_direct_mode(indio_dev);
*val = sign_extend32(be16_to_cpu(dat), 13);
return IIO_VAL_INT;
@ -561,7 +568,7 @@ static int ad5933_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
out:
mutex_unlock(&indio_dev->mlock);
iio_device_release_direct_mode(indio_dev);
return ret;
}
@ -657,18 +664,17 @@ static void ad5933_work(struct work_struct *work)
unsigned char status;
int ret;
mutex_lock(&indio_dev->mlock);
if (st->state == AD5933_CTRL_INIT_START_FREQ) {
/* start sweep */
ad5933_cmd(st, AD5933_CTRL_START_SWEEP);
st->state = AD5933_CTRL_START_SWEEP;
schedule_delayed_work(&st->work, st->poll_time_jiffies);
goto out;
return;
}
ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
if (ret)
goto out;
return;
if (status & AD5933_STAT_DATA_VALID) {
int scan_count = bitmap_weight(indio_dev->active_scan_mask,
@ -678,7 +684,7 @@ static void ad5933_work(struct work_struct *work)
AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,
scan_count * 2, (u8 *)buf);
if (ret)
goto out;
return;
if (scan_count == 2) {
val[0] = be16_to_cpu(buf[0]);
@ -690,7 +696,7 @@ static void ad5933_work(struct work_struct *work)
} else {
/* no data available - try again later */
schedule_delayed_work(&st->work, st->poll_time_jiffies);
goto out;
return;
}
if (status & AD5933_STAT_SWEEP_DONE) {
@ -703,8 +709,6 @@ static void ad5933_work(struct work_struct *work)
ad5933_cmd(st, AD5933_CTRL_INC_FREQ);
schedule_delayed_work(&st->work, st->poll_time_jiffies);
}
out:
mutex_unlock(&indio_dev->mlock);
}
static int ad5933_probe(struct i2c_client *client,
@ -723,6 +727,8 @@ static int ad5933_probe(struct i2c_client *client,
i2c_set_clientdata(client, indio_dev);
st->client = client;
mutex_init(&st->lock);
if (!pdata)
pdata = &ad5933_default_pdata;